In semiconductor apparatuses, various resin materials are used as sealing members for covering and protecting semiconductor devices. Particularly, sealing members in optical semiconductor apparatuses are required to have excellent barrier properties against corrosive gas typified by sulfur compounds such as SOX and H2S.
Methylsilicone (methylsilicone sealing members) excellent in heat resistance is mainly used as sealing members in optical semiconductor apparatuses, particularly, for the purpose of illumination. For example, use of a resin composition containing methylsilicone supplemented with ladder-type silsesquioxane, an isocyanurate compound, and a silane coupling agent as a sealing agent is known to improve sulfidation resistance against SOX (see e.g., Patent Literature 1).